SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6776c8148bea4f12d13bdc4fb98c2678e7857108507e80b59439ac9aa7ea60d' 
  AND token = 'TxS3LsANehmrelh67COs7JRvaEGPc1DJLve4JlN/MdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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