SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '775f5d0b94fbf7439d22e604f128f2301006e20456afda967e1553028a4ad3ab' 
  AND token = 'ESpyhKM/zzK/KHm91KQtMxZCXuHrtLoQRYm2Q6Ns3Po=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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