SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '71891001279ac50bb64054b0f4f768c6e63da65786ffea7fb97b1f2f24a7c055' 
  AND token = 'P4bxlzkxZsHIiquGfmfwMk6qY3h09A5fosimYTMwkHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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