SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '626a62928f991c44cb2dcf2d1084126f45939930975ec38dfaa410bd316bf57d' 
  AND token = 'a8GuphFT5CZTFoteoelPE9yjpSepUORaGKJ5RNy61No=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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