SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b804a6892c2f61829b8535ac5772d02357ee752ac5597dbeb4123621e10c55db' 
  AND token = 'SRTnWA6spNonngx2Atm60UPF9CGbrV6UO4JKFV53Rjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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