SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc4ed98bd9f0fe91879387f5f5f886f7ded89e4ca8b51678775770af0a794a24' 
  AND token = 'uAfEMoJIOEdZkjEKbsdYFtBxyTHCsHLV+/L1W5ZZATM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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