SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c45c85fbc9f3b659b77e51d3f550dd34d3fc860d2c8641882144b321cfe8aa2' 
  AND token = 'QhDQOMymuu4xerEHP2YYypBgxepsjsfpPfuyfjYN4vY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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