SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78f0f2928b23207fe4adfd371084e90b2d36056febef221224b86b5a9130a187' 
  AND token = 'B+mQPQmhXlfywfaedUf4Jbqc1R5WMccaNOOTdZE2/Is=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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