SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83149d309b355e1993fac3426d95784acb2f5caeb650b9cdbe1b39a7767be3a0' 
  AND token = 'crBLwVgvjohVM5wwd5LCr+2ChXanHUQaLVBvdYX/DkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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