SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26e17a236ac952f61491038b29fbf91ec21809c050c5622c65057cbf767b66e4' 
  AND token = 'xW/Lx2PcZl+rtPcDNiyDfw//ePjfaONnX1VznNsxjbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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