SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a310f9ef6a00c9a3d842d36584595157323829ab14914a545d2ce2ebf6cc92a2' 
  AND token = 'icKsLgvdCvg+x+iZrqfTASAoMBJeznTnQR8wK49enOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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