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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b810e5a9a45f89ef60e2a15e4e8a19b598d1f3a18b8dcb3e65c57f0375ada49b' 
  AND token = 'WikCSNB7X2xXuF5e+DpvpQp1x7EohzyVxWx/DmhbdkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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