SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79cda7ae77bf4fcae7358205f091905b402d7785c12d2683d020016f96f0d5e1' 
  AND token = 'EKJpAJWcL/Ea8GRJCkTM5xz1aSFXOz3x8xkWsDMlYEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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