SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d11395349864e756f434df52e9b575e05cccee9d1bda84cb241e5355c94923e' 
  AND token = 'WT987S37mEaYAfSvMLb41kabRWzWiiShrb3LrX4/P+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}