SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15529d9008c36d46b151b151056c793ead9dfbb3c530def2080afd41b8f033df' 
  AND token = 'ipr4NTQfFjLiQ587JNFRB5tQSNfcgVLbGnNDiTSIAQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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