SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '950706cea99ad4ce83c2e8b9652f449ab13008265a238e427d2805a103abdb7f' 
  AND token = 'NRTUAFY31KCrR/LswCnOma+iDqNS6SBFOgZxo0FswSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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