SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dff5935939ed37d372fc218f8b9418f1149ff89bf8278bfbc53debb21872bf21' 
  AND token = 'ZZoR1cWr/PN9GVzuqgKh0652Yb1U7bklhBPkjl6melQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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