SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f052492c87710e76d1bec843e239dec0e5bc65e32a87a51af2160e4141e51d1b' 
  AND token = 'gSJLUcutZpU71hFFtlvD+3uaSJiFE3dMnx1GrQsOONE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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