SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e58c05b5e29487ca27eb035d767429d002995175118dacc1f3b375078481f623' 
  AND token = 'MShe8K85XBMO3fOW1rVbBNxnITGxy05ejsXIE4Nutbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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