SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e4fe03b67b598cefc53eef9d990dadd327bcf93c2148ec5e017f97091f3b67c' 
  AND token = '1Sov6olNWsVgwUA6pyP6btNKrESLIczyl/P/OXPryj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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