SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26cfa16684994a0fb4be1136b26cb0c0420dd5314bbafa3ab402e8a7f92db8a9' 
  AND token = 'p9jcUERgTR2HcUVYsJmSj3i2yiPWLRtT4aLBCNgVT34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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