SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f95cbf296ce74785846ceda96358d8f00a41f031fc2c6592b5884af25ae6ee1c' 
  AND token = 'RvYw7xdb2xcYpPcjjHzqFqMYy39PTh2zBHlo8rt+/8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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