SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efae3bd3aafd08c5bfda2b032eb9ca7a9bb9b032d8743ca98be630206e1f51d6' 
  AND token = 'D5hAR+ach9mWrZohdMdWMUKM1Yz2fYJteFxnWEpftZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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