SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '973d89c03216a317b1abc2d7b9752a9c1cda25fed4dd443a14f78f35db6d4c7e' 
  AND token = 'R6+Qwvm8/V0OgauUBUjPDFDhD5rCtNJ1ZpEihz+Kppc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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