SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a95ab79f6ca0fdf785e66ad86ed92a11b0935402159ad917aa031dfecbd633d' 
  AND token = '6rMi4hXmE7AGlBOTRwA0bQpJKxA1ij+UtxoNDQ23bAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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