SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4b7c78f8132977d38c5ec3c2b9269b4fa653f21ffeaef178d696779f4e95df4' 
  AND token = '8uFxYvl79zV/LYvK/FbEMtv7dB0DFGrrcgCnJ88wD+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}