SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '166c8d864d655e3f3fd977426e878f96366d149e5c516f2b40320bff26c6089d' 
  AND token = 'W3FF6nmKppUHbTAfT6W83yUFDz1mgCKrHWp2qmBcKeo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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