SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe5e60255d85f291c243d60c68957b3e5f5c2f8dda666e38c9f7b96277d08058' 
  AND token = 'kQsw/EPwncYgPG2FOhHClX1AXdFYUnKlLDetgqjynow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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