SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3cdd51dcace5543c34f2dac275747456789ada70d4b3076fa6e3a5241925318' 
  AND token = 'rUu1NdR2FG5Z6bHDB1K3lhfrR1xyRqjrRNxG446+cDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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