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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d9cb433eedbd0daf0f4c2f0c0f5e6cfe1d86ede4f853f899cfcc26fa47672a3' 
  AND token = 'VPIy5Kwal4tbCfWLBfGJu1sh+8EmuPY3GZr9vXEaw2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}