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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4c3b915f8cc68f3dba6a6c88f93ec80d54681bd6e7b64502f8da389b0b0d5c2' 
  AND token = 'nsarUB/DN30Lza9udVSNo3qHxo+z8PVbp8boKYmqmjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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