SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2357f8bd88ce1856ee71a1d5fd8765e4d5ae660ed57c6f2c04c8f818517b6f6a' 
  AND token = 'j/Nw/xw4rTJv1C/fRoNc49V3gzqrBx7CpZ+Xzr+EF/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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