SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9378d78997aac9a9f26c4c526b24e2626b7bee4e28b99fd389a139e421542d17' 
  AND token = '9/X89K07nlrgyFbGodgg947R6xLmQWCI3w8FYSYawRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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