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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e21b6b8b0b20e0734cd89c9ecc005e3e7591e69c1f1838da66aab6cf26b15605' 
  AND token = 'gQmgTtJDiic/IOK1uhIDF507pQPe3ZDVMnnhbqwpCTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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