SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '707f1734571c80b8f564af63ab695cba51853539e46bc5d02273afdd0fb2a488' 
  AND token = 'Mozb11ltn0pqvHogRaCYGhkzgoAVFRc9km6LMljZzps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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