SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45e54ba507aa9fa188275f742cb06f40a3cd0a1e1067a2c38f06f315124f2a15' 
  AND token = '+YUlqkx/hP4PVijfVz5fNwLS1eAHT3eG/Xx7JgQKuZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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