SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfa8357ce13dc867dfb89d35d7b65a4c4dfce69a3ee6ae2251207c8298d95d7f' 
  AND token = 'Gug3IYkvpC6hiTOp4RYIdl83cAXaTkJug2HMytGy0WY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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