SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8001673667212509e62c55c3c533b219c63ab81e8b4d4763b23b541641a2f3d' 
  AND token = '8gDdYtrD5Iweg7pPNEEvCO8F6kkT7QCxLB2hrWhcvs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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