SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '662cdf943f434d46a668b4872c53676ba9c62c05853a632d4dc8621b3edad673' 
  AND token = 'm4XKNhbmzqfJp3Jjuq4phXZ/PYjGzPAOFhfjO4kqw28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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