SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b01496409fdb5e00f37cb03bc41a92e50cbff6defaf4049076d1b5369fcca7e2' 
  AND token = '6WQcowSWJdtFYJqRRsc21EI37WeUAzNvrMnb1RO6f2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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