SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75823da59c905e884f5a993108f856d56c13921b22390b016181b83c34b1e2f0' 
  AND token = 'HM/J/3PeoYFmxaiNmnmNxTbfgTjlc9gpn4MCHxplLiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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