SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb16e4f54859ee853b0d18576a2777e941ecc5ccf7856fde9e0e962f0911347f' 
  AND token = '0dzXEmJKqQJ5dIe/JdymRLCQo4nxgZourG+GgxFU/qQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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