SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82c7d0e6b80adf36948983f645116b04accffcd640d838e27dec16371584479f' 
  AND token = 'wgkvvEuWjWpZk6uoR6WqFRG49lWAoP5slBKr4SedH2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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