SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aeff437a506535acd286cc037b8c7dab5d839ffda3861ea094487da7e318f98f' 
  AND token = 'MuU4kslVOlmaylW4hflgVju+Kx9qg1kWqH9iG4bMCI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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