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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c9d15d8ca3348f21cf6f577d12dde266db3ea78b0ddb679de3329aa16b89b11e' 
  AND token = 'B/1NuOiVWYe2avNdzlIXDiVzO3aSJsqgwlCtrdmI5ns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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