SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5698e39cba2493080bcd33a0312e008d4601f0f99f06524a844203c49e277eef' 
  AND token = '00zAlzATcR8vu+khbSrfBeazgX+ynXtJMPYPvVpJNDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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